1. Field of the Invention
This invention relates to 17-substituted steroids and their use in the treatment of androgen-dependent and oestrogen-dependent disorders, especially prostatic cancer and breast cancer respectively.
2. Description of the Related Art
The 17.alpha.-hydroxylase/C.sub.17-20 lyase enzyme complex (hereinafter "hydroxylase/lyase") is known to be essential for the biosynthesis of androgens and oestrogens. In the treatment of androgen-dependent disorders, especially prostatic cancer, there is a need for strong inhibitors of hydroxylase/lyase. Certain anti-androgenic steroids are well known, for example Cyproterone acetate (17.alpha.-acetoxy-6-chloro-1.alpha.,2.alpha.-methylene-4,6-pregnadiene-3, 20-dione). Many other steroids have been tested as hydroxylase/lyase inhibitors. See, for example, PCT Specification WO 92/00992 (Schering AG) which describes anti-androgenic steroids having a pyrazole or triazole ring fused to the A ring at the 2,3-position, or European Specifications EP-A 288053 and EP-A 413270 (Merrell Dow) which propose 17.beta.-cyclopropylamino androst-5-en-3.beta.-ol or -4-en-3-one and their derivatives.